1. Field of the Invention
The present invention relates to an LED (light emitting diode) lamp device.
2. Description of the Related Art
Heretofore, as LED lamps, a round type and a surface mount device (SMD) type have been known. When these LED lamps are used as, for example, a vehicle lamp, a print board to which a lead of the LED lamp has been soldered is fitted into a case part to constitute an LED lamp device, and this LED lamp device is attached in a predetermined position of the vehicle. The print board is wired to an illumination control device of the vehicle, whereby ON/OFF of the LED and brightness at the LED lighting-up time are controlled by a switch or a control circuit of the vehicle.
In the above-described conventional LED lamp devices, since the print board to which the LED lamp is attached is made of resin, heat-radiating property for heat from the LED lamp or for heat at the mounting time can become insufficient. In order to solve such the problem, the present applicant has proposed, in the prior patent application (Patent Document 1), constitution in which the circuit part is formed of a metal plate thereby to achieve efficient heat-radiation and heighten reliability, and in which there is little influence of heat at the mounting time of the LED lamp thereby to obtain a good manufacturing yield.    Patent Document 1: JP-A-2003-258314    Patent Document 2: JP-A-11-103096    Patent Document 3: JP-A-2000-216442
In the LED lamp device disclosed in the Patent Document 1, an LED lamp, a resistive element, a diode, and the like are coupled on the same side of a metal plate constituting a circuit part. Under this constitution, space for each part and a coupling area of each part onto the metal plate must be secured on the same side, so that miniaturization of the device is difficult. Therefore, the invention has mainly object to provide, in an LED lamp device having a circuit part formed of a metal plate, constitution which enables further miniaturization of the device. Further, the invention has another object to improve heat-radiating property.